Self-stabilizing flotation module

ABSTRACT

A module having open-bottomed containers from which liquid is displaced by gas for lifting submerged material. The containers are held in an inclined position so that excess gas can escape gradually, and mounted relative to each other so that no net moments are imposed on the module.

United States Patent [151 3,648,314 Garrison 1 Mar. M, 1972 [54]SELF-STABILIZING FLOTATION 3,372,996 3/1968 Barrett etal ..114/53 M D L2,682,246 6/1954 Best ..114/53 [72] Inventor: Dwight Wesley Garrison,Picayune, Miss.

[73] Assignee: General Electric Company, Daytona Beach, Fla.

[22] Filed: Dec. 10, 1970 [21] Appl. No.: 96,881

[52] [1.8. CI. ....l14/53, 114/52 [51] Int. Cl. ..B63c 7/10 [58] Fieldof Search ..114/50, 52, 53

[56] References Cited UNITED STATES PATENTS 3,512,493 5/1970 HaIIanger ndi4/3 m Primary Examiner-Evon C. Blunk Assistant Examiner-l. KennethSilverman Att0meyRaymond H. Quist, Allen E. Amgott, Henry W. Kaufmann,Frank L. Neuhauser, Oscar B. Waddell and Joseph B. Forman [57] ABSTRACTA module having open-bottomed containers from which liquid is displacedby gas for lifting submerged material. The containers are held in aninclined position so that excess gas can escape gradually, and mountedrelative to each other so that no net moments are imposed on the module.

3 Claims, 3 Drawing Figures PAIENTEDMAR 14 I972 SHEET 1 OF 2 INVENTOR.Dwighf W. Garrison BY ATTORNEY.

PMENTEDHAR 14 1972' SHEET 2 OF 2 INVENTOR.

Dwighr W. Garrison ATTORNEY.

SELF-STABILIZING FLOTATION MODULE BACKGROUND OF THE INVENTION Thisinvention relates to a flotation module for lifting submerged equipmentor minerals.

As heavier loads at greater depths are desired to be lifted, the utilityof pressure vessels decreases because of the increasing weightpenalties. Although light weight flotation modules using thedisplacement of water by a gas have been employed, their usefulness hasbeen impeded because of a lack of stability resulting in sudden drops inbuoyancy.

SUMMARY OF THE INVENTION In a preferred form of the invention, three ormore openbottomed containers are secured together in a module with theirlongitudinal axes upwardly inclined toward the vertical axis of themodule. The containers are arranged so that any moment due to buoyancyis counterbalanced. The inclined attitude of the containers has twobeneficial results: any excess gas will escape gradually from theuppermost portion of the container bottom instead of from an arbitrarylocation as would occur with a nominally vertical container; and if onecontainer is more buoyant than the others it will rise and spill gasuntil the buoyancies are equalized resulting in a self stabilizingmodule.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic isometric of aflotation module in accordance with the invention;

FIG. 2 is a schematic cross section of one container of the module ofFIG. 1; and

FIG. 3 is a schematic cross section of a gas generating device carriedby a container.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a flotationmodule employing four open-bottomed containers is illustrated. Thecontainers l-l6 may be of a thin wall construction since they are notintended to experience differential pressures. Each container has areinforcing ring I8 at its bottom edge secured to a bottom brace 20 Agas introducing or generating device 22 is provided so that a gas may beintroduced into the containers when desired. Gas venting valve 23permits easy submergence of the module by releasing gas. When the moduleis submerged and the containers are filled with gas, the resultingbuoyancy will produce an upward force on the top of each of thecontainers which is transmitted to top braces 24 through top reinforcingstructure 26.

As is more clearly shown in FIG. 2, the upward inclination of thelongitudinal axis of container 14 (typical of each of the containers)results in a residual amount of water at the bottom of the containerwhich is not displaced by incoming gas. It should be observed that ifthe inclination of container 14 were increased, gas would escape in thevicinity of region 26. Such an increased inclination would occur ifcontainer 14 contained a greater volume of gas than container 10,thereby having greater buoyancy. As gas escapes from container 14,however, its buoyancy is reduced until the total module achieves astabilized attitude.

Because of the built-in inclination of containers -16, gas

will escape (whether due to an excess of gas or an increase ininclination) in a gradual rather than an abrupt manner. This reduces thetendency of the module to oscillatereleasing gas first from one side andthen the opposite.

Various means may be utilized for introducing gas into containers 10-16.For example, hoses can be connected to valve 28 and to a source ofcompressed gas. At depths where a hose arrangement becomes cumbersome,however, a gas generator carried on the container can be employed. InFIG. 3, a gas generator 22 is illustrated which is secured in the top ofeach container.

A cylindrical pressure vessel 30 is provided to act as both thecontainer for a solid propellant grain 32 and the combustion chamber inwhich this propellant will be burned. Propellant grain 32 may be of anysuitable solid propellant material such as ammonium nitrate. An igniter34 may be positioned at one end of vessel 30 and may comprise a squib ofexplosive material 36 containing a bridge wire 38 which will cause thesquib to be ignited when a sufficient current passes through it. Currentis supplied to bridge wire 38 by electrical cable 39. Igniter 34 alsoserves to close one end of pressure vessel 30 so that all gas which isgenerated within this vessel will be discharged at the opposite end.Closure 40 on the lower end of pressure vessel 30 incorporates gasdischarge conduit 42 and one-way valve 44. One-way valve 44 comprises aball 46 which serves to prevent liquid from entering vessel 30 throughconduit 42 by closing orifice 48 under the biasing efi'ect of spring 50and the pressure of any liquid within conduit 42. Generation of gaswithin pressure vessel 30 dislodges ball 46 and permits the gas to bedischarged through conduit 42 and into the container.

In operation, the self stabilizing flotation module of this inventionmay be placed in the water and submerged by venting entrapped gas. Atthe desired location, it may be attached to an object, and the waterwithin the containers displaced by gas.

While a particular embodiment of a self stabilizing flotation module hasbeen shown and described, it will be evident that changes andmodifications can be made without departing from the spirit of theinvention and the scope of the appended claims.

I claim:

I. A self stabilizing flotation module for providing thrust in a liquidenvironment comprising:

at least three open-bottomed containers;

means connecting said containers to each other and maintaining them in afixed position relative to each other; the longitudinal axis of each ofsaid containers being upwardly inclined toward the vertical axis of saidmodule;

said containers being so sized and arranged that when filled with gasthe sum of the moments of force on said module is zero; and

means for introducing a gas into said containers for displacing liquidtherefrom.

2. A self stabilizing flotation module in accordance with claim Iwherein:

said means for introducing a gas into said containers is a gasgenerating device secured to the container.

3. A self stabilizing flotation module in accordance with claim 2wherein:

said gas generating device includes a solid propellant grain of ammoniumnitrate.

* =3 #i 1F i

1. A self stabilizing flotation module for providing thrust in a liquid environment comprising: at least three open-bottomed containers; means connecting said containers to each other and maintaining them in a fixed position relative to each other; the longitudinal axis of each of said containers being upwardly inclined toward the vertical axis of said module; said containers being so sized and arranged that when filled with gas the sum of the moments of force on said module is zero; and means for introducing a gas into said containers for displacing liquid therefrom.
 2. A self stabilizing flotation module in accordance with claim 1 wherein: said means for introducing a gas into said containers is a gas generating device secured to the container.
 3. A self stabilizing flotation module in accordance with claim 2 wherein: said gas generating device includes a solid propellant grain of ammonium nitrate. 